Prediction model construction and structure improvement of attack angle in centrifugal compressors return channel

The return channel, as a critical component of centrifugal compressors, significantly impacts the overall economic efficiency and reliability of compressor operation. To enhance the overall efficiency of the centrifugal compressors, this study develops a flow field simulation model for centrifugal compressors to investigate the flow characteristics of the return channel under varying attack angles. By integrating a total pressure loss model with multi-stage cooling theory, predictive models for single-stage and multi-stage return channel attack angles are established. The accuracy of these models is verified through simulations and experimental data. Based on the predictive models, the return channel structure is optimized, resulting in a 2.11% increase in polytropic efficiency. Additionally, internal flow performance under different inlet widths is analyzed visually through contour plots, further validating the predictive model and structural improvements. This study provides a valuable reference for the optimized design of return channel structures.